Oak  street 

unclassified  BULLETIN  NO.  8 


\J 


South  Dakota  School 
of  Mines 


Departments  of  Geology,  Chemistry,  Mining 

„nd  Metallurgy.  u[)lvERjlTy  OF  ILLINOIS 


THE 


PRESIDENT’S  OFFICE, 

Cement  Resources 


OF  THE 


Black  Hills. 

Including  Tests  on 

Cements  Made  from  Black  Hills  Material 


BY 


CLEOPHAS  C.  O’HARRA,  Ph.  D. 

M.  F.  COOLBAUGH,  M.  A. 

M.  A.  EHLE,  Jr.  E.  M. 

CHAS.  H.  FULTON,  E.  M. 


RAPID  CITY,  S.  D. 
JULY/  1908. 


BULLETIN  NO.  8 


South  Dakota  School 
of  Minty1’' OF 


ILLINOIS 


PRESIDENTS  OFFICE 

Departments  of  Geology,  Chemistry,  Mining 
and  Metallurgy. 


THE 

Cement  Resources 

OF  THE 

Black  Hills. 

Including  Tests  on 

Cements  Made  from  Black  Hills  Material. 


BY 


CLEOPHAS  C.  O’HARRA,  Ph.  D. 

M.  F.  COOLBAUGH,  M.  A. 

M.  A.  EHLE,  Jr.  E.  M. 

CHAS.  H.  FULTON,  E.  M. 


RAPID  CITY,  S.  D. 
JULY,  1908. 


Rapid  City  Printing  Company, 
Rapid  City,  S.  D. 


Letters  of  Transmittal. 


SOUTH  DAKOTA  SCHOOL  OF  MINES. 

Rapid  City  , S.  D.,  July  i,  1908. 

Dear  Sir 

I have  the  honor  to  transmit  herewith  a paper  by 
C.  C.  O’Harra,  M.  F.  Coolbaugh,  Mark  Ehle  and  C. 
H.  Fulton  on  the  Cement  Resources  of  the  Black  Hills 
of  South  Dakota.  I submit  it  with  the  recommenda- 
tion that  it  be  published  as  Bulletin  No.  8 of  the 
School  of  Mines. 

Respectfully, 

CHARLES  H.  FULTON, 

President. 

To  The  Hon.  E.  C.  Ericson,  President, 

Regents  of  Education. 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/cementresourcesoOOohar 


Introduction. 


The  great  increase  in  the  use  of  Portland  Ce- 
ment has  drawn  attention  to  possible  sources  of  raw 
material.  The  Black  Hills  of  South  Dakota  are  es- 
pecially favored  in  this  respect,  both  as  regards  the 
quantity  available,  and  the  purity  of  the  material.  In 
the  experimental  work  on  the  cements  care  was  taken 
to  have  it  thorough  and  representative.  Much  more 
work  was  done  than  is  recorded  in  the  bulletin. 

The  editor  desires  to  express  thanks  to  Mr.  Willi- 
am A.  Coursen  for  the  efficient  aid  given  in  the  con- 
struction and  operation  of  the  experimental  cement 
furnace;  also  to  thank  Mr.  J.  B.  Read  for  services  in 
connection  with  the  making  of  analysis,  etc.  The  ed- 
‘**or  also  expresses  his  gratitude  to  his  colleagues,  Pro 
fessors  O’Harra,  Coolbaugh  and  Ehle  for  their  able 
labors  in  making  this  bulletin  thorough  and  represen- 
tative. 

CHARLES  H.  FULTON, 

Editor. 


PART  I. 

THE  GEOLOGY  OF  THE  BLACK  HILLS  CEMENT 
MATERIAL. 

C.  C.  O’HARRA,  Ph.  D. 


The  Geology  of  Black  Hills 
Cement  Material. 

C.  C.  o'HARRAJ  PH.  D. 

The  Black  Hills  region  is  bountifully  supplied 
with  deposits  available  for  the  manufacture  of  good 
cement.  Until  recently  little  attention  has  been  given 
to  the  experimental  study  of  these  materials  and  in 
this  bulletin  chief  attention  is  directed  toward  the  ex- 
aminations of  two  or  three  formations  of  special  prom- 
ise favorably  situated  with  reference  to  railroads. 

The  formations  chiefly  studied  are  what  in  geo- 
logic literature  are  known  as  the  Minnekahta  lime- 
stone, the  Graneros  shale,  and  the  Niobrara  argillace- 
ous chalk.  Experimental  work  indicated  that  by  a 
proper  mixture  of  materials  from  the  Minnekahta  and 
the  Graneros  formations  a compound  can  be  made, 
suited  in  every  way  for  the  manufacture  of  a high 
grade  Portland  cement,  while  the  Niobrara  can  fur- 
nish material  of  proper  composition  for  the  making 
of  excellent  natural  cement.  Of  the  limestones,  the 
Minnekahta  is  the  only  one  of  the  region  deemed 
worthy  of  consideration  at  this  time.  The  Pahasapa 
is  the  great  limestone  formation  of  the  Black  Hills, 
making  long  lines  of  high  white  escarpment  facing 
on  all  sides  the  central  part  of  the  uplift,  but  it  con- 
tains much  maganesia  and  too  little  attention  has  been 
paid  to  the  possible  magnesia-free  portions  to  allow 
for  any  reliable  statement  as  to  favorable  localities 
where  this  limestone  might  be  profitably  exploited. 
Such  other  limestones  as  occur  within  the  region  are 
thin  or  impure  and  are  often  inclined  to  considerable 


IO 


variation  in  character,  hence  have  not  been  given  spec- 
ial attention. 

The  shale'bearing  formations  are  abundantly  rep- 
resented and  several  of  them  give  evidence  of  possible 
value  used  in  combination  with  the  Minnekahta  lime' 
stone.  In  addition  to  the  Graneros  already  mentioned 
there  are  the  Pierre,  the  Niobrara,  the  Carlile,  the  Mor- 
rison, and  possibly  other  formations  that  merit  care- 
ful examination,  should  an  exhaustive  study  be  made 
of  all  available  materials.  That  the  geologic  position 
of  the  various  formations  may  be  better  understood  a 
complete  generalized  geologic  section  of  the  Black 
Hills  region  is  here  given. 

The  Minnekahta  Limestone.  The  Minnekahta 
limestone,  known  commonly  in  early  geological  papers 
as  the  Purple  Limestone,  although  seldom  more  than 
fifty  feet  in  thickness  is  one  of  the  prominent  out- 
cropping formations  of  the  Black  Hills  region.  It  is 
a close-textured,  thinly-bedded,  grayish  limestone  with 
frequently  a slight  pinkish  or  more  often  a purplish 
tinge,  hence  the  earlier  name.  The  bedded  nature 
of  the  rock  is  much  concealed  on  fresh  surfaces,  but 
weathering  reveals  the  condition  in  a very  definite  way. 
Near  the  middle  of  the  formation  the  nature  of  the 
bedding  is  such  as  to  allow  for  slightly  more  rapid 
weathering  than  elsewhere  and  this  feature  generally 
reveals  itself  in  unmistakable  manner.  Near  the  bot- 
tom the  bedded  nature  is  again  pronounced  and  the 
rock  here  contains  considerable  argillaceous  material. 
The  lowest  beds  which  are  generally  much  ironstained 
are  not  commonly  exposed.  In  some  localities  where 
they  are  exposed  the  limestone  breaks  up  into  numer- 
ous small  lenticular  concretionary  bodies  within  which 
fairly  well-preserved  fossils  are  found.  In  general, 
however,  the  formation  is  markedly  free  from  fossils, 
although  not  quite  so  much  so  as  was  earlier  supposed. 
Mr.  N.  H.  Darton  of  the  United  States  Geological  Sur- 
vey records  the  identification  of  Bakewelha , Hdinondia r 
and  Nuculana. 


Map  showing  outcrop  of  the  Minnekahta  formation 


II 


The  Minnekahta  is  underlain  by  a thin  series  of 
soft  clay  shales  known  as  the  Opeche  formation  and 
is  overlain  by  a thicker  series  of  soft  sandy  shales, 
the  Spearfish  formation,  commonly  known  as  the  Red 
Beds.  The  dip,  sometimes  steep,  sometimes  low,  varies 
in  a more  or  less  undulatory  manner,  but  in  general  it 
follows  the  nature  of  all  of  the  periclinal  sedimentary 
rocks  of  the  region  in  that  it  is  distinctly  apocentral, 
that  is,  it  dips  outwardly  on  all  sides  from  the  higher 
central  portion  of  the  main  Balck  Mills  uplift. 

The  outcrops  are  unusually  prominent  every 
where.  The  relatively  hard,  more  or  less  sharply  dip' 
ping  limestone  between  the  soft  shale  beds  readily  lends 
itself  to  the  production  of  a bold  topography.  Hun- 
dreds of  streams,  constant  and  intermittent  flowing 
radially  from  the  central  area  of  the  uplift  run 
across  the  formation  and  each  carves  for  itself  a 
V-shaped  gateway  to  the  red  valley  beyond.  On  the 
outer  slopes  wherever  the  dip  is  considerable,  the  rock 
is  nearly  bare  of  soil  and  vegetation  although  the  pine 
trees,  Pinus  ponderosa,  cling  tenaciously  to  it  wher- 
ever a roothold  can  be  secured.  • The  inner  line  of  out- 
crops is  a continuous  succession  of  prominent  escarp- 
ments which,  facing  the  central  area  of  the  uplift  dome, 
stand  out  in  bold  relief  as  they  overlook  the  sharply, 
trenched  Opeche  below. 

The  width  of  outcrop  varies  greatly.  Where  the 
dip  is  steep  as  for  example  along  Beaver  creek  and  the 
lower  portion  of  Gillette  canyon  east  of  Newcastle  and 
on  the  immediate  flanks  of  several  of  the  lacolithic 
areas  which  interrupt  the  general  foothill  structure, 
the  width  of  the  outcrop  is  reduced  to  a minimum. 
Elsewhere  where  the  dip  is  slight  and  gently  undulat- 
ing, such  as  in  the  southern  Hills  west  and  north- 
west of  Hot  Springs,  in  the  northern  Hills  near  Spear- 
fish  and  still  better,  along  the  western  side  of  Cold 
Spring  creek  in  Wyoming  extensive  areas  are  cap- 
ped by  this  limestone.  Local  irregular  and  isolated 


12 


FORMATION 

Character 

Average 

THICKNESS 

Feet 

AGE 

Laramie 

Massive  Sandstone  and 

Tertiary  and 
Pleistocene 

Shale  

2,500 

Ofetaceous 

Fox  Hills 

Sandstone  and  Shale... 

250-500 

do 

Pierre  Shale 

Dark  Gray  Shale 

1,200 

do 

Niobrara 

Chalk  and  Calcareous 
Shale 

225 

do 

Benton  Group— 

Carlile  formation.. 

Gray  Shales  with  thin 

sandstones,  limestone 
and  concretionary 
layers.  

500-750 

. do 

Greenhorn  Lime- 

Impure,  slabby  lime- 

50 

do 

Graneros  Shale 

Dark  shale  with  lenses 
of  massive  sandstone 
in  its  lower  part  at 
some  places , 

900 

do 

Dakota  Sandstone  . 

Massive  buff  sandstone 

32-150 

do 

Fuson 

Very  fine  grained  sand- 
stone and  massive 
shale.  White  to  pur- 
ple color 

30-100 

do 

Minnewasta  Lime- 

stone   

Gray  limestone  

0-30 

do 

Lakota 

Massive  buff  sandstone 
with  some  shale 

200-350 

do 

Morrison  Shale 

Pale,  grayish  green 
shale.  — 

0-150 

Jurassic 

Unkpapa  Sandstone 

Massive  sandstone 
white,  purple,  red 
buff  . 

0-250 

do 

Sundance 

Thin  limestones.  Dark 
drab  shales  and  buff 
sandstones.  Massive 
sandstone  at  base 

60-400 

do 

Spearfish 

Red.  sandy  shale  with 
gypsum  beds 

350-500 

Triassic 

Minnekahta  L i m e- 

stone 

Thin-bedded,  gray  or 
purple  limestone 

30-50 

Permian 

Opeche 

Red,  slabby  limestone 
and  sandy  shale 

90-130 

Permian 

Minnelusa 

Sandstones,  mainly  buff 
and  red;  in  greater 
part  calcareous.  Some 
shales  and  thin  lime- 
stones included 

400-450 

Carboniferous 

Paliasapa  Lime- 

do 

stone  

Massive  gray  limestone 

250-500 

Englewood  Lime- 

do 

stone  

Rink,  slabby  limestone 

25 

White  wood  Lime- 

stone   

Buff  colored,  mottled 
limestone,  with  green- 
ish shales  at  top 

0-80 

Ordovician 

Dead  wood  

Red-brown  quartzite, 
calcareous  shales  and 
sandstones,  locally 

conglomeratic,  partly 
massive » • • 

4-150 

Cambrian 

13 


areas  are  common.  Such  are  the  tongue'like  extension 
between  Hot  Springs  and  Alabaugh  canyon,  the 
elongated  irregular  dome  alongside  the  Chicago  & 
Northwestern  railway  northwest  of  Rapid  City,  and 
the  more  or  less  circular  outcrop  about  Green  moun- 
tain, Strawberry  mountain,  Inyan  Kara,  Warren 
peaks,  Elkhorn  peak,  Crook  mountain  Bear  Butte*  etc. 

The  formation  affords  many  fine  springs,  a feat- 
ure of  much  interest.  It  is  the  source  of  the  abund- 
ant thermal  waters  at  Hot  Springs  and  Cascade 
springs  and  of  colder  waters  at  many  other  places. 
Analyses  as  elsewhere  given  show  this  limestone  to  be 
of  excellent  character  for  various  industrial  uses.  It 
serves  for  the  manufacture  of  high  grade  lime  and 
is  indeed  the  chief  source  of  such  material  for  the 
Black  Hills  region.  It  was  used  for  a considerable 
time  in  the  smelter  at  Rapid  City  in  the  reduction  of 
the  siliceous  gold  ores  of  the  northern  Hills,  the  lime- 
stone being  obtained  alongside  the  Chicago  & North- 
western railroad  three  miles  northwest  of  Rapid  City. 
It  is  now  being  extensively  utilized  in  the  cyanide 
plants  of  the  Homestake  Gold  Mining  Company  in 
Lead,  their  two  kilns  of  modern  make  being  constant- 
ly in  operation  at  the  quarry  on  Elk  creek  near  Doyle 
on  the  Burlington  railroad  a short  distance  above  Pied- 
mont. The  following  analyses  of  this  limestone  indi- 
cate its  superior  nature  in  the  preparation  of  a high- 
grade  Portland  cement.  Analysis  No.  I is  by  Profes- 
sor M.  F.  Coolbaugh  of  the  School  of  Mines,  the  ma- 
terial coming  from  an  outcrop  alongside  the  Missouri 
river  and  Northwestern  railroad  near  the  old  Canyon 
Lake  site,  four  miles  west  of  Rapid  City.  Analysis  No. 
2 and  No.  3 are  from  samples  taken  near  Newcastle. 
These  two  analyses  are  given  in  Bulletin  No.  315  of 
the  U.  S.  Geological  Survey.* 


♦Ball.  Sydney  H.  Portland  Cement  Materials  in  Eastern 
Wyoming.  Bulletin  No.  315,  U.  S.  Geol.  Survey,  p.  232-244. 


14 

Table  No.  2. 


Analysis  No.  1. 

Silica,  SiC>2 
Ferric  Oxide,  Fe2  O3 
Alumina,  AI2  O3 
Titanium  oxide,  Ti02 
Lime,  CaO 
Magnesia,  MgO 
Sulphur,  S 

Alkalies,  ^2<0, 

Phosphorus  pentoxide,  P2  O5 
Carbon  dioxoxide,  CO2 
Water,  H2  O 


1.21  Percent 
0.16 
0.47 
trace 
54.56 
0.41 
0.11 
trace 
trace 
trace 
42.30 
0.91 


Total  100.13 

Loss  on  ignition  42.95  percent. 

Table  No.  2 A. 


Analysis  Nos.  2 and  3. 


No.  1. 

No.  2. 

Silica,  SiCL 

1.08  Percent  1.42  Percent 

Alumina,  AI2  O3 

0.33 

0.68 

Ferric  oxide,  Fei*2  O3 

0.77 

0.40 

Manganese  oxide,  MnO, 

0.46 

0.11 

Lime,  CaO, 

53.40 

52.85 

Magnesia,  MgO, 

0.57 

0.72 

Sulphuric  anhydride, S03,  0.12 

0.12 

Alkalies, 

0.36 

0.16 

0.76 

0.30 

Water  at  100°  C 

0.20 

0.10 

Ignition  loss 

42.92 

42.78 

Total 

100.37 

100.24 

The  Graneros  Shale. 

The  Graneros  shale  is 

the 

st  member  of  what  is 

frequently  known  as 

the 

Benton  group.  Lying  as  it  does  just  outside  the  main 
Cretaceous  hogback  its  outcrop  completely  encircles  the 
Black  Hills  uplift  as  a broad  belt  of  low  undulating 
hills  and  valleys  and  serves  as  the  innermost  fringe 
of  the  great  plains  of  the  Black  Hills  region. 


i5 


The  formation  is  made  up  distinctively  of  fine- 
grained dark  gray  to  black  shale,  but  there  is  consid- 
erable modification  of  this  simple  character  in  many 
places,  especially  in  that  portion  of  the  area  lying  with- 
in the  borders  of  Wyoming.  Here  a well-defined 
four-fold  character  generally  shows  itself,  viz.,  first,  a 
lower  portion  of  fine  black  fissile  shale  150  to  300  ft. 
thick;  above  this,  massive  grayish-buff  sandstone  of 
varying  thickness  up  to  40  ft. ; following  this  a series 
250  to  300  ft.  thick  of  dark  shales  of  hard  texture 
which  weather  to  a distinct  grayish  white  color ; lastly, 
at  the  top  a series  of  very  black  shales  400  to  500  feet 
thick,  much  resembling  the  shales  of  the  lowest  mem- 
ber. In  that  portion  of  the  Black  Hills  region  lying 
within  South  Dakota  the  four  fold  character  is  less 
prominent  and  particularly  is  this  true  so  far  as  con- 
cerns the  eastern  and  southern  portions  of  the  uplift. 

The  sandstone  member  varies  greatly  in  thick- 
ness and  hardness;  sometimes  it  stands  out  in  bold 
cliffs  much  like  the  Dakota  sandstone  whose  texture 
and  grayish-buff  color  it  closely  simulates.  Elsewhere 
ii  is  much  concealed  and  over  considerable  areas  it  is 
thin  or  absent.  Near  Newcastle  where  this  member 
reaches  local  prominence  the  rock  contains  petroleum 
as  indicated  by  certain  bore  holes  and  by  small  flows 
from  several  natural  springs.  The  sandstone  shows  in 
various  places  along  the  eastern  side  of  the  Black  Hills, 
as,  for  example,  at  Rapid  City  and  Hermosa,  but  here 
it  partakes  more  of  the  nature  of  greatly  elongated 
lenses  and,  except  for  a few  lenticular  hills,  is  of  little 
or  no  topographic  significance. 

The  hard  grayish  shale  member,  now  commonly 
designated  as  the  Mowrie  beds,  from  Mowrie  creek 
near  Buffalo,  Wyoming,  where  it  was  first  studied,  is 
prominent  in  much  the  same  areas  as  the  underlying 
sandstone  except  that  it  partakes  less  of  the  lenticular 
nature  of  the  latter.  Its  greatest  thickness  is  apparent- 
ly in  the  vicinity  of  Belle  Fourche  and  northwest  of 
there  along  the  Belle  Fourche  and  the  Little  Missouri 


i6 


rivers.  Ridges  often  result  from  the  more  rapid  wear- 
ing away  of  the  softer  shales  and  these  ridges  by  con- 
trast of  color,  by  topographic  importance  and  by  their 
general  wooded  covering  serve  admirably  in  delineat' 
ing  the  outcrops  of  these  beds  from  the  generally 
non-wooded  darker  shales  of  the  lower  and  the  up- 
per members.  The  beds  are  further  characterized  by 
the  presence  of  multitudes  of  fish  scales  in  almost 
all  good  exposures.  Southeast  of  Belle  Fourche  the 
gray  color  and  the  indurated  nature  become  gradually 
less  distinctive  and  the  fish  scales  grow  fewer  in  num- 
ber until  at  Rapid  City  only  the  closest  scrutiny  es- 
tablishes the  presence  of  any  portion  of  the  member. 

The  lowest  member  needs  little  more  character  de- 
scription than  already  given.  With  the  exception  of 
the  passage  beds  of  alternating  shales  and  sandstones 
near  the  bottom  and  occasional  bands  of  fair  to  good 
sized  lime-clay  concretions  it  is  practically  entirely  a 
fine  fissile,  black  shale.  It  lends  itself  to  especial  at- 
tention here  in  that  the  shale  material  used  with  lime- 
stone from  the  Minnekahta  formation  in  the  prepara- 
tion of  the  Portland  cement  described  elsewhere  in  this 
bulletin  was  obtained  from  this  member.  The  follow- 
ing chemical  analyses  shows  its  favorable  character. 
No.  i is  by  Professor  Coolbaugh  of  the  Shool  of  Mines 
and  represents  material  obtained  a few  hundred  yards 
north  of  the  Hinrichs-Lanphere  saw  mill  in  Rapid 
City.  No.  2 represents  material  from  near  New- 
castle and  is  recorded  in  Bulletin  No.  315  of  the  U.  S. 
Geological  Survey.* 

*Ball.  Sydney  H.  Portland  Cement  Materials  in  Eastern 
Wyoming.  Bulletin  No.  315,  U.  S.  Geol.  Survey,  p.  232  244. 


Table  No.  3 


Analysis  No.  1 


Silica,  SiOs, 

58.74  Percent 

Ferric  oxide,  Fes  O3 

3.87 

Alumina,  Als  Og" 

18.97 

Titanium  oxide,  Ti02  , 

0.71 

Lime,  *CaO, 

0.93 

Magnesia,  MgO, 

1.62 

Sulphur,  S, 

0.21 

Alkalies,  §2  0^ 

1.49 
• 0.58 

Phospheros  pentoxide,  Ps  O5 

1.44 

Manganese  oxide,  MnO, 

trace 

Loss  on  ignition 

11.93 

Total 

100.24 

Table  No.  4. 

Analysis  No.  2. 

Silica,  SiOs 

58.82  Percent 

Alumina,  Als  O3  , 

16.43 

Ferric  oxide,  Ees  O3 

4.47 

Manganese  oxide.  MnO. 

0.24 

Lime,  CaO, 

0.54 

Magnesia,  MgO, 

1.68 

Sulphuric  anhydride,  SO3 

1.32 

Alkalies,  K2200’' 

0.33 

2.18 

Water  at  100°  C, 

6.39 

Ignition  loss, 

7.93 

Total 

100.33 

There  is  little  or  no  reason  for  believing  that  much 
of  the  shales  of  the  higher  members  of  the  formation 
would  not  lend  themselves  as  freely  to  the  production 
of  good  cement  as  the  lowest  member,  although  lit- 
tle experimental  work  has  been  carried  on  by  way  of 
demonstrating  their  real  value  for  such  purpose. 

The  upper  black  shale  member  much  resembles  the 
lowest  member.  It  is  generally  thicker  and  is  inclined 
to  be  more  abundantly  supplied  with  lime-clay 


i8 


concretions.  These  concretions  sometimes  reach 
a diameter  of  five  or  six  feet  or  more. 
Thin  bands  of  limestone  are  occasionally  found. 
Some  of  these  are  highly  fossiliferous  and, 
while  never  of  great  thickness,  they  occasionally  are 
able  to  control  the  topography  sufficiently  to  out- 
line ridges  and  hills  of  some  prominence. 

The  formation  taken  as  a whole  is  well  exposed. 
The  outcrop  is  generally  wide.  This  is  more  particu- 
lary  true  around  the  northern  end  and  along  the  west- 
ern side  of  the-  Hills  where  for  many  miles  it  serves 
as  a wide  valley  bed  for  the  Belle  Fourche  and  the 
Little  Missouri  rivers  and  their  tributaries,  the  width 
of  outcrop  in  places  reaching  ten  or  a dozen  miles  or 
more.  Along  the  eastern  foothills  the  outcrop  is  nar- 
rower. From  Whitewood  creek  southward  to  Spring 
creek  it  varies  from  one  to  four  or  five  miles.  South 
of  Spring  creek  it  is  much  concealed  by  unconformable 
Tertiary  deposits.  Throughout  the  entire  region  allu* 
vial  deposits  cover  up  considerable  areas  along  the 
streams  and  higher  gravels  veneer  many  of  the  gentle 
slopes  and  flat  topped  hills  and  ridges.  The  alluvial 
deposit  is  particularly  prominent  along  the  Belle 
Fourche  river  and  the  Little  Missouri  river  in  the 
northern  and  northwestern  part  of  the  area  and  along 
lower  Beaver  creek  and  certain  portions  of  the  Chey- 
enne river  in  the  southern  part.  This  covering  pre- 
vails to  a less  extent  elsewhere  but  is  of  significance 
wherever  the  formation  is  crossed  by  streams  of  a me- 
andering nature. 

The  Graneros,  like  the  Minnekahta,  is  favorably 
situated  with  reference  to  railroads.  Northwest  of 
Newcastle  and  between  Newcastle  and  Edgemont  the 
Burlington  is  built  upon  this  formation,  for  many 
miles.  This  road  could  easily  reach  it  by  short  exten- 
sion near  Piedmont  or  near  Spearfish  if  such  should 
be  desired.  At  Rapid  City  the  formation  is  convenient 
to  the  Missouri  river  and  Northwestern,  to  the  Chi- 
cago, Milwaukee  and  St.  Paul,  and  to  the  two  lines  of 


19 


the  Chicago  & Northwestern.  South  of  Rapid  City 
to  Buffalo  Gap  the  Chicago  & Northwestern  touches  it 
at  many  points.  North  of  Rapid  City  to  Whitewood 
this  road  lies  within  the  red  valley  but  even  here  easy 
access  is  permitted  to  the  Graneros  by  the  many  notches 
through  the  intervening  hogback  ridges.  North  of 
Whitewood  the  Belle  Fourche  branch  of  the  Chicago 
& Northwestern  railroad  quickly  passes  outside  the  red 
valley  to  the  formation.  It  then  follows  the  general  di- 
rection of  outcrop  to  and  beyond  Belle  Fourche,  being 
flanked  on  both  sides  by  exposures  in  most  conven' 
ient  mariner.  In  much  the  same  way  west  of  Belle 
Fourche  ihe  formation  lies  convenient  to  the  Wyoming 
and  Missouri  River  railroad. 

The  Niobrara  Formation.  The  Niobrara  forma- 
tion lies  just  beneath  the  Pierre  shale.  Compared  to 
the  Pierre  it  is  thin,  being  seldom  more  than  225  ft. 
thick  and  around  the  northern  end  of  the  uplift  it  is 
approximately  100  ft. 

The  material  is  very  soft,  is  highly  calcareous, 
and  partakes  more  or  less  of  the  nature  of  an  easily 
pulverized  chalky  limestone.  Fresh  material  is  of  a 
blun  h-gray  color  but  outcrops  are  generally  well 
weathered  and  disintegrated  and  in  this  condition  the 
material  is  of  a rich  creamy  yellow  color. 

The  formation  seldom  develops  any  topographic 
features  of  significance  but  its  pronounced  yellow  color 
renders  the  formation  conspicious  whenever  the  out- 
cropping surface  is  broken.  The  fossil  oyster,  Ostrea 
congesta,  occurs  in  abundance  in  occasional  thin  in' 
durated  bands  and  this  also  serves  as  a distinctive 
feature. 

Near  the  head  of  the  Little  Missouri  river  west  of 
the  Bear  Lodge  range  and  in  the  vicinity  of  Newcastle 
where  local  disturbances  have  given  the  formation  a 
steep  dip  the  width  is  only  a few  yards  but  frequently 
elsewhere  it  reaches  one  mile  or  more. 

In  view  of  the  fact  that  the  formation  outcrops 
continuously  and  in  a fairly  regular  manner  around 


20 


the  Black  Hills  and  is  so  readily  distinguished  in  the 
field  it  serves  nicely  as  a stratigraphic  guide  and  deline- 
ates in  an  excellent  manner  the  plain  ward  extent  of 
the  more  pronounced  structural  features  of  the  Black 
Hills  uplift. 

The  Niobrara  is  the'  formation  that  affords  much 
of  the  raw  material  for  the  Portland  cement  plant  at 
Yankton  in  the  southeastern  part  of  the  state.  The 
interesting  feature  with  reference  to  the  Black  Hills 
area  is  that  the  chemical  nature  of  the  rock  'as  revealed 
by  analysis,  while  not  uniform,  indicates  that  this 
formation  can  furnish  in  places  within  the  Black  Hills 
area  a most  excellent  material  for  natural  cement.  Its 
physical  condition  is  almost  everywhere  particularly 
favorable.  The  shaly  pulverent  nature  of  the  mater- 
ial would  allow  for  easy  excavation  and  doubtless 
steam  shovel  operation  could  be  carried  on  to  consider- 
able depth.  The  chemical  nature  varies  and  is  not  ah 
ways  satisfactory  but  the  following  analysis  by  Pro' 
fessor  Coolbaugh  of  the  School  of  Mines  from  mater- 
ial near  Antelope  creek  ten  miles  east  of  Tilford  shows 
a particularly  favorable  composition  and  indicates  the 
possibility  of  utilizing  this  material  to  most  excellent 
advantage : 

Table  No.  5. 


Silica,  SiC>2, 

Ferric  oxide,  Fe2  On  and 
Alumina,  AI2  O3 
Lime,  CaO, 

Sulphur,  S 
Magnesia,  MgO, 

Alkalies,  K2  O,  and  Na2  O, 
Loss  on  ignition 

Total 


15.51  Percent 
5.80 

38.85 

trace 

1.08 

1.50 

36.67 

99.41 


This  may  be  more  readily  compared  with  the  analy- 
sis of  Portland  cement  manufactured  from  the  Min- 
nekahta-Graneros  mixture  given  elsewhere  in  this  bul- 


21 


letin  by  recalculating  so  as  to  omit  reference  to  loss  on 
ignition.  The  analysis  thus  arranged  is  as  follows  : 


Table  No.  6. 


Silica,  SiOs, 

24.65  Percent 

Ferric  oxide,  Feg  O;}  and 
Alumina,  AI2  O;* 

9.16 

Lime,  CaO, 

61.36 

Sulphur.  S,  (estimated) 

0.20 

Magnesix,  MgO, 

1.72 

Alkalies.  K2  O and  Na2  O, 

2.52 

Total 

99.61 

Table  No.  7. 


Silica  Si02. 

Ferrie  Oxide  and  1 
Lime  CaO, 
Magnesia,  MgO, 
Alkalies, 

Sulphur, 

Loss  on  ignition 

Total 


No.  4. 

' Near  Rapid  Oity. 

22.47 

mina  9.80 
25.01 
1.54 
0.75 
1.84 

38.25 

( 

99.66 


No.  5. 

Bear  Butte  Piere 
6.81 
3.23 
46.75 
0.93 
1.43 
trace 
39.56 

99.71 


The  Burlington  and  Missouri  River  railroad  fol- 
lows the  outcrop  of  the  formation  for  some  miles  near 
Ardmore  and  near  Newcastle  and  crosses  it  again  near 
Moorcroft.  The  Chicago  & Northwestern  railroad 
crosses  it  near  Buffalo  Gap,  then  follows  it  fairly  close- 
ly to  Rapid  City.  Just  east  of  Rapid  City  the  Pierre, 
Rapid  City  & Northwestern  cuts  across  the  formation 
in  a particularly  favorably  manner  while  the  Chicago, 
Milwaukee  & St.  Paul  could  reach  similarly  good  out- 
crops near  by  with  little  side  trackage.  Between  Rapid 
City  and  Whitewood  the  formation  outcrops  in  a wide 
belt  several  miles  east  of  the  railroad  but  this  could 
be  easily  reached  if  desired  through  the  various  gaps 
in  the  hogback  ridges. 


22 


The  Morrison  Formation . The  Morrison  forma- 
tion of  early  Cretaceous  or  late  Jurassic  age  lies  just 
beneath  the  Lakota  sandstone.  It  does  not  completely 
encircle  the  Hills,  there  being  a considerable  space  in 
the  southeastern  portion  of  the  uplift  where  it  is  ab- 
sent.. Along  the  eastern  side  of  the  Hills  it  is  under 
lain  by  the  massive  soft  Unkapapa  sandstone  but  along 
much  of  the  western  portion  of  the  uplift  the  Unkpapa 
is  absent  and  it  is  underlain  by  the  Sundance  forma- 
tion. 

The  formation  is  made  up  of  shales  and  thin  nod- 
ular bands  of  white  argillaceous  limestone,  the  shales 
greatly  predominating.  Sometimes  the  clay-lime  nodu- 
les are  of  little  or  no  significance  and  occasionally  thin 
shaly  sandstones  appear,  the  latter  showing  best  in  the 
Bear  Lodge  mountains.  The  shales  carry  more  or  less 
carbonaceous  matter  and  vary  much  in  color.  Olivine 
green  predominates  in  fresh  exposures  but  pale  green- 
ish gray,  yellowish  gray,  pink,  red,  maroon,  chocolate, 
purple,  and  black  are  not  infrequently  observed.  A 
characteristic  and  fairly  common  feature  of  the  for* 
mation  is  the  presence  of  large  saurian  bones  near  the 
bottom  of  the  formation.  Several  localities  have  af* 
forded  good  specimens. 

The  formation  where  best  exposed  varies  in  thicks 
ness  up  to  160  feet  or  more.  In  the  Bear  Lodge  moun- 
tains and  southward  it  varies  from  40  ft.  to  160  ft. 
Along  the  northeastern  side  of  the  Hills  the  thickness 
varies  in  much  the  same  way.  On  the  Oelrichs  quad- 
rangle it  is  absent. 

Exposures  are  good  in  many  places  *and  conven- 
ient to  the  railroads.  The  Chicago  & Northwestern 
parallels  the  outcrop  all  the  way  from  Rapid  City  to 
Whitewood  and  could  easily  tap  many  of  the  expos- 
ures by  short  spur  trackage,  the  outcrops  being  all  to 
the  east  of  the  track  and  at  various  convenient  heights 
above  the  main  line.  The  Burlington  and  Missouri 
River  railroad  crosses  the  formation  between  Edge- 


Scale 

0 10  20  30  <0  00  Julies 

1  J l i J I 


Map  showing  outcrop  of  the  Morrison  formation 


..  K . 


v 

i 


23 


mont  and  Minnekahta  and  is  fairly  convenient  to  it 
near  Newcastle  and  Piedmont.  The  Wyoming  and 
Missouri  River  railroad  follows  the  formation  for 
some  distance  near  Aladdin. 

Little  experimental  study  has  been  given  this  for- 
mation but  it  is  worthy  of  consideration.  An  analy- 
sis* of  material  obtained  near  Newcastle  gives  the  fol- 
lowing favorable  composition : 

Table  No.  8. 


Silica,  Si  O2, 

45.78  Percent 

Alumina,  AI2  O3 

12.92 

Ferric  oxide,  Fe2  O3 

3.95 

Manganese  oxide,  MnO, 

0.83 

Lime,  CaO, 

0.56 

Magnesia,  MgO, 

0.73 

Sulphuric  anhydride,  SO3 

0.48 

Alkalies,  Na2  O, 

0 64 

K2  O, 

0.50 

Water  at  100°  C, 

8.26 

Ignition  loss,  largely 

26.32 

carbonaceous  matter 

Total 

100.42 

The  Carlile  Formation.  The  Carlile  formation 
outcrops  immediately  within  the  Niobrara  and  consti- 
tutes the  upper  portion  of  the  Benton  group.  It  is 
made  up  of  a series  of  thin  black  shales  with  occasional 
thin  impure  sandstone  and  limestone  bands.  In  places 
the  limestone  is  quite  argillaceous  and  takes  on  the 
form  of  large  concretionary  or  lenticular  masses. 
These  sometimes  contain  fossils. 

In  the  Devils  Tower  quadrangle  the  formation  is 
made  up  of  three  fairly  distinct  divisions,  viz.,  an  up- 
per division,  chiefly  shale,  300  feet  thick;  a middle  di- 
vision 125  feet  thick,  concretions  and  shale;  and  a low- 
er division  200  feet  thick,  mostly  shale.  Elsewhere 
this  threefold  nature  is  absent  or  is  not  sufficiently 
prominent  to  disclose  itself  in  any  characteristic  man- 

*Ball.  Sydney  H.  Portland  Cement  Materials  in  Eastern 
Wyoming.  Bulletin  No.  315,  U.  S.  Geol  Survey,  p.  236. 


24 


ner.  The  total  thickness  varies  from  about  400  feet 
near  Buffalo  Gap  to  about  700  feet  in  the  vicinity  of 
Newcastle.  The  shale  portions  much  resembles  the 
shales  of  the  Pierre  and  the  Graneros  and  doubtless 
the  chemical  composition  is  much  the  same. 

The  formation  is  readily  accessible  to  the  various 
railroads  in  much  the  same  manner  as  the  overlying 
Niobrara.  Since  it  has  not  been  carefully  studied  as 
to  possibilities  in  the  way  of  affording  ingredients  for 
cement  manufacture  further  description  need  not  be 
given  at  this  time. 

The  Pierre  Formation.  The  Pierre  formation  is 
the  latest  Cretaceous  formation  that  outcrops  within 
the  immediate  Black  Hills  region.  It  completely  encir- 
cles the  uplift  as  a broad  belt  and  is  one  of  the  greatest 
formations  of  the  Plains  region.  West  of  the  Hills  its 
outcrop  averages  perhaps  five  or  six  miles  in  width. 
Northeast,  southeast,  and  south  of  the  Hills  it  reaches 
several  times  this  width  while  to  the  east  of  the  Hills 
it  extends  far  beyond  the  limits  of  the  regions  under 
discussion.  Every  railroad  entering  the  Hills  traverses 
the  formation  for  several  or  many  miles  and  good  ex- 
posures are  abundant  and  convenient. 

The  thickness  of  the  formation  is  given  as  ap- 
proximately 1200  feet.  The  material  is  almost  wholly 
black  shale.  Weathered  surfaces  show  lighter  color 
and  in  the  lower  portion  where  some  lime  enters  into 
the  composition  the  color  is  inclined  to  a dull  yellowish 
color.  Lime  and  lime'iron  concretions  are  abundant  at 
several  horizons.  These  are  often  highly  fossiliferous. 
particularly  those  in  the  upper  part  of  the  formation 
and  the  invertebrate  forms  that  they  contain  are  varied 
in  character  and  often  beautifully  preserved.  The  for 
mation  is  abundantly  exposed  and  readily  distinguish- 
ed. For  further  details  of  structure,  distribution  and 
phsical  character  of  this  formation  as  well  as  for  the 
Carlile  the  reader  is  referred  to  the  various  publications 
listed  on  a subsequent  page. 


25 


Little  attention  has  been  given  to  the  accurate 
chemical  nature  of  the  shales.  One  analysis*  made 
from  material  obtained  one  mile  above  Spencer  siding 
on  the  Burlington  and  Missouri  River  railroad  south- 
ly  known  as  the  “red  beds.”  This  formation  complete- 
southeast  of  Newcastle,  is  as  follows : 

Table  No.  9. 


Silica,  Si02, 

60.66  Percent 

Alumina,  AI2  O3 

22.13 

Ferric  oxide,  Fe2  O3 

1.21 

Manganese  oxide,  MnO, 

0.41 

Lime,  CaO, 

1.59 

Magnesia,  MgO, 

1.54 

Sulphuric  anhydride,  SO3 

0.43 

Alkalies,  Na2  O, 

0.53 

K2O, 

3.16 

Ignition  loss 

9.28 

Total 

99.97 

The  above  analysis  shows  certain  undesirable  per- 
centage of  ingredients  but  field  observation  furnish 
good  reason  for  believing  that  a series  of  analyses  of 
material  selected  from  various  localities  would  show  a 
fair  number  with  favorable  proportions  of  the  var- 
ious important  elements. 

Gypsum.  A brief  word  concerning  the  nature 
and  occurrence  of  Black  Hills  gypsum  may  be  of  inter- 
est here  in  view  of  the  fact  that  gypsum  enters  in  a 
minor  way  into  the  manufacture  of  cement. 

The  deposits  of  Black  Hills  gypsum  occur  at  var- 
ious horizons  within  the  Spearfish  formation,  popular- 
ly known  as  the  “red  beds.”  This  formation  complete- 
ly encircles  the  Hills  and  good  exposures  seldoms  fail 
to  show  gypsum,  nearly  pure  white,  in  sufficient  quant- 
ity and  of  sufficient  purity  to  be  of  commercial  value. 
The  deposits  are  extensive  and  convenient.  They  are 
sometimes  lenticular  but  more  often  they  occur  in  beds 

*Ball.  S.  H.  Portland  Cement  Mat.  in  Eastern  Wyoming. 
Bui.  315,  U .S.  G.  S.  p.  238. 


26 


of  nearly  uniform  thickness  and  in  some  places  where 
the  outcrop  is  favorable  these  white  beds  may  be  traced 
across  the  landscape  for  many  miles  as  they  stand  out 
in  prominent  contrast  to  the  enclosing  red  sandy  shales. 

The  gypsum  is  of  a high  degree  of  purity  and  for 
several  years  has  been  utilized  in  the  manufacture  of 
stucco  or  plaster.  Two  plants  are  now  in  active  opera- 
tion, one  at  Hot  Springs  and  one  near  Rapid  City.  The 
Hot  Springs  plant  has  been  in  interrupted  operation 
for  several  years.  The  Rapid  City  plant  was  placed 
in  commission  early  in  the  year  1908.  Both  plants  are 
convenient  to  large  bodies  of  good  raw  material. 

Analysis  of  the  Hot  Springs  gvpsum  made  by  Pro- 
fessor Coolbaugh  show  the  following  composition.  No 
1 is  from  a thirteen  foot  bed  near  the  bottom  of  the  ex- 
posure and  No.  2 is  from  a four  foot,  the  two  being 
separated  by  one  foot  of  red  shale  carrying  only  thin 
seams  of  gypsum.  Both  beds  are  utilized. 


Table  No.  10. 


Silica,  SiOs, 

0.12 

Ferric  oxide,  Fes  Ob 
Alumina,  Als  Ob 

0.12 

Sulphuricanhydride,SOB 

47.77 

Lime,  CaO, 

83.00 

Magnesia,  MgO, 

a 10 

Loss  on  ignition 

20.85 

Totol 

101.97 

0.09  Percent 


0.06 

44.86 

32.89 

0.28 

21.41 

98.59 


Mr.  Steiger  of  the  U.  S.  Geological  Survey  lab- 
oratory gives  the  following  analysis  of  material  from 
near  Cascade  Springs:* 


*Dartcn,  N.  H.  Gypsum  Deposits  in  South  Dakota. 
Bulletin  No.  223,  U.  S.  Geological  Survey,  p.  76-78. 


Map  showing  outcrop  of  the  gypsum- bearing  Spearfish  formation 

Reproduced  from  U.  S.  G.  S.  Bulletin  No.  223.  New  railroads  inserted 


27 

Table  No.  1 1. 


Lime,  CaO, 

32.44  Percent 

Magnesia,  MgO, 

0.33 

Alumina,  AI2  O3 

0.12 

Silica,  Si  O2 

0.10 

Sulphuric  anhydride,  SO:* 

45.45 

Carbon  dioxide,  CO2, 

.85 

Water,  H2  O, 

20.80 

Total 

100.09 

Additional  Literature.  The  reader  who  may  wish  to 
examine  more  fully  into  the  details  of  distribution  and 
description  of  the  various  geological  formations  de- 
scribed or  mentioned  in  this  paper  will  find  much  ad- 
ditional information  in  the  following  atlas  folio  publi- 
cations of  the  U.  S.  Geological  Survey : 

Darton,  N.  H.,  Oelrichs  folio.  No.  85,  1902. 

Darton,  N.  H.  Newcastle  folio.  No.  107,  1904. 

Darton,  N.  H.,  and  Smith,  U.  S.  T.  Edgemant  fo- 
lio No.  108,  1904. 

Darton,  N.  H.,  Sundance  folio,  No.  127,  1905. 

Darton,  N.  H.  and  O’Harra,  C.  G.  Aladdin  folio, 
No.  128,  1905. 

Darton,  N.  H.,  and  O’Harra,  C.  C.,  Devils  Tower 
folio  No.  150,  1907. 


PART  II. 

OUTLINE  FOR  THE  ANALYSIS  AF  CEMENTS 
AND  CEMENT  MATERIALS. 


M.  F.  COOLBAUGH,  M.  A. 


Outline  for  Analysis  of  Ce- 
ment and  Cement 
Materials. 

M.  F.  COOIvBAUGH,  M.  A. 

The  outline  scheme  for  the  analysis  of  cements 
will  serve  in  many  places  as  a scheme  for  the  analysis 
of  limestonesv  raw  mixtures,  shales  and  clays. 

Decomposition. — With  highly  silicious  material 
decomposition  can  be  effected  by  treatment  with  hy- 
drochloric and  nitric  acids,  filtration,  fusion  of  the  resi- 
due with  sodium  carbonate,  and  solution  of  the  fused 
mass  in  water  and  hydrochloric  acid.  Or  the  fusion 
may  be  made  directly  without  a previous  treatment 
with  acids.  For  the  decomposition  of  limestones  or 
unburned  mixtures,  ignite  material  with  one-half  to  an 
equal  weight  of  sodium  carbonate  and  treat  mass  with 
diluted  hydrochloric  acid. 

Silica. — Two  evaporations  are  essential  for  this 
determination  when  considerable  accuracy  is  required. 
Even  then  a complete  separation  is  not  effected,  as 
some  silica  will  be  found  with  the  iron  and  alumina 
precipitate.  Some  alumina  will  also  be  found  with  the 
dehydrated  silica.  Corrections  for  these  small  amounts 
of  impurities  are  not,  however,  necessary  in  technical 
work,  since  the  weights  tend  to  counterbalance  each 
other.  For  greater  accuracy,  the  silica  should  be 
driven  off  by  treatment  with  hydrofluoric  acid  and  a 
few  drops  of  sulphuric  acid.  The  residue  should  be 


32 


added  to  the  precipitates  from  the  ammonia  treatment. 

Iron  and  Alumina. — The  precipitates  of  iron  and 
aluminum  hydroxides,  which  contain  also  titantic-acid, 
ferric  phosphate,  and  a small  amount  of  silica,  is  puri- 
fied from  calcium  and  traces  of  manganese  by  solution 
in  nitric  acid  and  reprecipitation  with  ammonia.  The 
calcium  in  the  first  precipitate  is  caused  by  impurities  of 
ammonium  carbonate  in  the  ammonia,  or  by  carbon  di- 
oxide in  the  air  of  the  laboratory.  The  manganese  is 
mot  separated  even  by  two  precipitations  unless  the 
content  of  that  element  is  small.  If  this  is  not  the  case, 
separate  it  from  the  iron  and  aluminum  by  precipita- 
tion of  the  latter  as  basic  acetates  in  a dilute  acetic 
acid  solution  containing  sodium  acetate.  The  amount 
of  silica  is  separated  after  the  fusion  with  the  acid 
sodium  sulphate,  as  in  (3),  and  evaporation  of  the 
sulphuric  acid  solution  to  low  bulk.  The  weight  found 
here  should  be  added  to  that  already  found. 

Titanium  Oxide. — The  titanium  is  determined  in 
the. solution  from  the  titsation  of  iron  in  (3).  Add  ten 
c.c.  hydrogen  peroxide,  make  to  a definite  bulk,  and 
compare  color  with  that  of  a'  standard  solution  of 
titanium  treated  in  a similar  manner. 

Manganese. — This  is  determined  in  the  filtrate 
from  the  iron  and  alumina  precipitation.  It  is  precipitat- 
ed with  ammonium  sulphide,  dissolved  in  nitric  acid 
and  determined  colorimetrically  by  use  of  silver  ni- 
trate and  ammonium  persulphate. 

Lime. — Acidify  with  hylrochloric  acid  the  com- 
bined filtrates  from  the  aluminum  and  ferric  hydrox- 
ides precipitates,  or  the  filtrate  from  the  manganese 
determination,  heat  to  boiling,  add  10  to  12  c.  c.  of 
a saturated  solution  of  ammonium  oxalate  and  slowly 
neutralize  with  ammonia.  The  longer  the  time  taken 
for  neutralization  the  less  danger  there  is  of  contam- 
ination by  magnesium.  When  greater  accuracy  is  de- 
sired, the  calcium  oxalate  is  filtered,  ignited,  dissolved 


Scheme  for  Analysis  of  Cement. 


33 


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34 


in  hydrochloric  acid,  made  alkaline  with  ammonia, 
boiled  and  the  small  amount  of  aluminum  hydroxide 
filtered  out  and  added  to  that  already  found.  The  cal- 
cium is  reprecipitated  as  the  oxalate,  filtered,  ignited 
and  weighed  as  calcium  oxide,  or  filtered,  washed,  dis- 
solved in  sulphuric  acid  and  the  oxalic  acid  titrated 
with  potassium  permanganate. 

Magnesia. — For  an  accurate  determination  of  this 
substance,  the  first  precipitate  should  be  dissolved  in 
hydrochloric  acid,  two  c.  c.  of  a saturated  solution  of 
sodium  ammonium  phosphate  added,  and  then  am' 
rnonia,  drop  by  drop,  as  described  in  (6)  in  the 
scheme.  The  reason  for  the  second  precipitation  is 
that  the  normal  magnesium  ammonium  phosphate  is 
not  the  only  precipitate  formed  in  the  presence  of  a 
large  excess  of  ammonium  salts,  but  is  contaminated  by 
some  (NH4)4  Mg  (P04)2  which  yields  Mg2  P2Ot 
only  on  very  strong  ignition. 

Sulphur. — Ignite  the  material  with  one'half  its 
weight  of  sodium  carbonate  and  a small  amount  of  so- 
dium nitrate,  extract  with  water,  filter,  acidify  filt- 
rate with  hydrochloric  acid,  and  precipitate  the  sulphur, 
with  barium  chloride  as  barium  sulphate.  The  so- 
dium nitrate  is  added  to  oxidize  the  sulphur  from  the 
the  sulphide  to  the  sulphate  condition. 

Phosphoric  Anhydride. — For  this  determination 
treat  the  residue  obtained  in  the  sulphur  determination 
with  nitric  acid,  evaporate  to  dryness  to  remove  silica, 
take  up  in  dilute  nitric  acid,  filter,  treat  residue  with 
hydrofluoric  and  nitric  acids,  finally  with  nitric  acid 
alone  and  unite  solutions.  Precipitate  the  phosphorus 
with  ammonium  molybdate,  dissolve  precipitate  in  di- 
lute ammonia,  acidify  with  sulphuric  acid,  reduce  with 
zinc  and  titrate  with  potassium  permanganate. 

Carbon  Dioxide. — Decompose  the  material  with 
hydrochloric  acid  and  absorb  the  carbon  dioxide  in 
soda  lime  or  a solution  of  potassium  hydroxide. 

Alkalies. — For  this  determination  follow  the  well 


35 

known  method  of  Professor  J.  Lawrence  Smith,  the 
outline  of  which  is  given  in  the  scheme. 

Insoluble  Residue. — Decompose  material  slowly 
with  a io  per  cent  solution  of  hydrochloric  acid,  filter, 
dry,  ignite  and  weigh  the  residue. 

Loss  on  Ignition. — Blast  a weighed  sample  for  fif- 
teen minutes  in  a covered  platinum  crucible.  Cool  and 
weigh.  Check  the  loss  by  blasting  for  another  five 
minutes. 

REFERENCES. 

Report  of  the  Sub-Committee  on  Uniformity  in 
Analysis  of  Materials  for  the  Portland  Cement  In- 
dustry. J.  Soc.  Chem.  Ind.  Vol.  21,  p.  12-30. 

Analysis  of  Materials  for  the  Portland  Cement  In- 
dustry. By  W.  F.  Hillebrand.  J.  Am.  Chem.  Soc. 
Vol.  25,  p.  1180. 

The  Analysis  of  Portland  Cement.  By  Bertram 
Blount.  J.  Am.  Chem.  Soc.  Vol.  26,  p.  995. 

The  Technical  Analysis  of  Cements.  By  S.  F. 
Peckham.  J.  Am.  Chem,  Soc.  Vol.  26,  p.  1636. 

The  analysis  of  Silicate  and  Carbonate  Rocks.  By 
W.  F.  Hillebrand.  Bulletin  305,  U.  S.  Geological 
Survey. 


/ 


PART  III. 

THE  PREPARATION  OF  THE  CEMENT  FROM 
THE  RAW  MATERIAL  FOR  EXPERI- 
MENTAL PURPOSES. 


c.  h.  Fulton,  e.  m. 


The  Preparation  of  the 
Cement. 

C.  H.  FULTON,  E.  M. 

The  raw  material,  its  extent  and  composition,  for 
the  manufacture  of  the  cement  has  been  described  in 
in  Pan  I of  this  bulletin. 

The  limestone  used  in  making  the  cement  describ- 
ed below  is  from  a cut  on  the  Missouri  River  and 
Northwestern  R.  R.  near  Canyon  Lake  about  four 
miles  west  of  Rapid  City  and  has  the  following 
analysis. 


Silica 

1. 21 

Ferric  oxide 

...  .16 

Alumina  

...  .47 

Titanium  oxide 

Lime 

...54.56 

Magnesia  

. . . .41 

Sulphur  

.11 

Alkalies  

Phosphorous  pentoxide . . . . 

. . . . trace 

Carbon  dioxide 

. . .42.30 

Water  above  ioo°  C 

...  .91 

100.13 

Loss  on  ignition 

• • -42.95 

The  shales  used  is  from  the  foot  hills,  one-half 
mile  northwest  from  the  center  of  Rapid  City  and  has 
the  following  analysis : 


40 


j 


Silica  58.47 

Ferric  oxide 3.89 

Alumina  18.97 

Titanium  oxide 71 

Lime 93 

Magnesia  1.62 

Sulphur  21 

Potassium  oxide  1.49 

Sodium  oxide  58 

Phosphorous  pentoxide 1.44 

Manganese  oxide  trace 

Loss  on  ignition 11 .93 


100.24 

This  material  was  to  be  mixed  in  such  propor- 
tion as  to  make  a sound,  strong  Portland  Cement.  The 
composition  of  Portland  Cement  cannot  vary  within 
wide  limits  and  certain  ingredients  like  magnesia, 
.and  sulphuric  anhydride  must  be  low.  The  limit  on 
magnesia  is  usually  placed  at  4 per  cent  in  cement  and 
that  of  sulphuric  anhydride  at  1.75  per  cent.  As  re- 
gards the  absence  of  both  of  these  harmful  ingredi- 
ents the  raw  material  is  especially  favored. 

• * . ( 

The  necessary  constituents  of  Portland  Cement 
are  silica,  alumina  and  lime.  According  to  Le- 
Chatelier,  Portland  cement  clinker  consists  of  alit,  con- 
sidered to  be  tri-calcium  silicate  3CaO,  Si02  *vhich 
is  the  active  hardening  element,  and  celit,  considered 
to  be  tri-calcic  aluminate, — 3CaO,  A1 2 O 3 also  set- 
ting and  hardening  in  water.  There  are  also  present 
in  small  amounts  calcium  ferrate  and  mono,  and  dical- 
cium silicates. 

Richardson  states  that  the  components  of  cement 
are  present  in  the  clinker  as  two  solid  solutions,  alit — 
a solution  of  tricalcic  aluminate  in  tri-calcic  silicate 
and  celit,  a solution  of  dicalcic  aluminate  in  di-calcic 


41 


silicate.  The  ratio  of  alit  to  celit  may  vary  from  3 to 
6 to  1. 


According  to  Bleininger*  the  limits  of  composi- 
tion of  Portland  Cement  are  as  follows : 


Silica 19  to  26  per  cent 

Alumina 4 to  11 

Ferric  oxide 2 to  5 

Lime  58  to  67 

Magnesia  o to  5 

Sulphuric  anhydride  o to  2.5 

Alkalies  o to  3.0 

The  following  are  typical  cements  analyses.** 
Lehigh  Co.,  Penn.  Yankton,  S.  D.  Coldwater,  Mich* 


Silica  22.68 

Alumina  6.70 

Ferric  oxide  . . . 2.35 

Lime  62.30 

Magnecia  3.41 

Sulphuric 

anhydride  ...  1.88 

Alkalies  

Loss  on  ignition 


19.50 

7.70 

4-30 

60.00 

0.80 

2.80 

1.20 


21.22 

7-5i 

3-83 

6375 

0.82 

1.58 

1.02 


According  to  the  constitution  of  the  cement  there 
must  be  a definite  ratio  between  lime,  silica  and  al- 
umina which  for  American  cements  may  be  express- 
ed by  the  following  empirical  formula : 

hime^Silica-  x 2.7  + alumina  x 1. 

Many  cements  come  quite  close  to  this  composition 
though  more  generally  the  lime  falls  somewhat  below 
the  figure  obtained  by  the  calculation. 

The  dried  raw  materials,  the  compositions  of 
which  have  been  mentioned  were  mixed  in  the  pro- 
portion of  1 part  shale  to  3.30  parts  limestone,  after 
considerable  experimentation  with  somewhat  different 
mixtures,  this  proportion  yielding  the  best  result.  Ac- 


* Manufacture  of  Portland  Cements.  Bui.  No.  3,  Ohio 
Geol.  Survey. 

**From  Taylor’s  Practical  Cement  Testing. 


42 


cording  to  calculation  from 

analysis  this  mixture 

should  burn  to  a cement  of  the  following  composition : 

Silica 

Alumina  

••  7-43 

Ferric  oxide 

Lime 

• .65.51 

Magnesia  

. . 1.07 

The  actual  composition  of  the  cement  (sample  No. 

13)  is  as  follows: 

Silica  

, . .23.08  per  cent 

Alumnia  

. . 7.12 

Ferric  oxide 

. . 2.07 

Magnesia  

. . 1.08 

Lime  

. . 64.80 

Sulphuric  anhydride 

. . 0.66 

Potassium  oxide  

..  0.52 

Sodium  oxide  

. . 0.21 

Titanium  oxide  

. . 0.26 

Phosphorous  pentoxide.  . . 

• • 0.53 

Manganous  oxide 

Carbonic  oxide 

Total  

. 100.33  

In  the  burning  curves  shown  in  Fix.  11  this  ce- 

ment  is  represented  by  curves  9, 

12  and  13.  Curves  7 

and  8 are  those  of  a cement  made  of  1 part  of  shale, 
and  3.5  parts  limestone  and  0.04  parts  iron  ore  con- 
taining 80  per  cent  of  ferric  oxide,  this  last  being  ad- 
ded to  slightly  increase  the  iron  content  of  the  cement. 
This  cement  has  the  following  composition : 

Silica 

. .22.04  per  cent 

Alumina  

. . 8.05 

Ferric  oxide 

. . 2.67 

Lime  

• -65-53 

Carbonic  acid 

.016 

The  Preparation  of  the  Razv  Material. — The  lime- 

stone  and  shale  were  crushed  in 

a small  Gates  breaker 

(laboratory  size)  to  a one  quarter  inch  ring/and  dried 
at  approximately  ioo°  C.  Each  constituent  was  then 

43 


weighed  out  accurately  in  the  proper  proportion  and 
ground  by  a Braun  disk  grinder  so  that  all  of  it  passed 
a 150  mesh  laboratory  screen.  The  ground  products 
were  then  thoroughly  incorporated  by  mixing  on  rub- 
ber cloth,  after  which  in  most  instances  the  whole  was 
again  put  through  the  grinder  to  more  thoroughly  in- 
corporate it.  Grinding  the  raw  material  together  in 
the  pulverizer  was  not  very  satisfactory  as  the  more 
brittle  limestone  would  grind  first.  The  mass  was 
then  moistened  with  water  until  a ball  of  it  when 
squeezed  in  the  hand,  would  just  hold  together,  and 
briquetted  in  a foot  power  cupel  machine,  to  briquet- 
tes 1.25  in.  in  diamater  and  1 in.  deep.  After  drying 
to  expel  all  moisture,  these  briquettes  were  ready  for 
burning.  A batch  of  material  usually  weighed  2200 
grams,  500  grams  of  shale  being  taken  as  the  unit. 

Cement  Burning.  For  the  proper  burning  of  ce- 
ment a high  temperature  is  necessary  as  the  usual  tem- 
perature required  is  between  1400°  and  1500°  C.  The 
precise  temperature  depends  upon  the  composition  of 
the  cement  mixture  and  to  some  extent  upon  the 
length  of  time  consumed  in  burning.  Cement  mixt- 
ures high  in  alumina,  silica,  or  ferric  oxide  require  a 
lesser  temperature  for  combination  of  the  constituents 
than  cements  high  in  lime.  Highly  aluminous  ce- 
ments are,  however,  undesirable  as  they  usually  prove 
defective.  The  amount  of  ferric  oxide  in  a cement  is 
largely  incidental  and  determined  by  the  composition 
of  the  raw  materials  and  cannot  ordinarily  be  varied 
without  disturbing  the  important  relation  of  silica  to 
lime  and  to  alumina.  In  the  material  used  in  the  de- 
scribed experiments  the  limestone  is  very  pure,  and 
carries  practically  lime  only,  while  the  shale  contains 
the  alumina  and  silica,  so  that  a variation  in  the  al- 
umnai  also  includes  one  of  the  silica  contents  of  the 
cement. 

The  briquettes  after  burning  make  cement 
“clinker.”  The  appearance  of  the  clinker  is  an  indr 
cation  of  the  proper  burning  of  the  cement,  and  also 


44 


indicates  roughly  if  the  composition  is  approximately 
corret.  Good  clinkfer  should  be  hard,  but}  brittle, 
somewhat  porous,  but  of  sufficient  specific  gravity. 
The  specific  gravity  of  the  burnt  cement  is  the  best 
general  indication  of  proper  burning.  1 Depending 
somewhat  upon  composition  the  specific  gravity  of 
the  ground  cement  should  be  from  3.10  to  3.20.  These 
figures  refer  to  cement  that  has  been  stored  for  some 
\veeks.  If  the  specific  gravity  is  taken  just  afer  burn- 
ing it  will  range  from  3.15  to  3.25.  Taking  the 
figures  for  stored  cement  a gravity  below  3.10  in- 
dicates unburning  and  one  above  3.20,  overburning. 
The  clinker  from  cements  high  in  lime  are  often  rather 
light  and  porous,  and  that  from  cements  high  in  alum- 
ina, dense  and  compact,  relatively  speaking.  The  last 
mentioned  kind  of  clinker  is  very  apt  to  “dust”  when 
taken  from  the  furnace,  e.  g.,  to  fall  apart  into  powd- 
er on  cooling. 

The  Experimental  Furnace. — The  furnace  for 
the  burning  of  the  cement  mixture  should  be  so  con- 
structed that  a temperature  of  1500°  C.,can  be  obtain- 
ed with  it.  The  generating  of  this  temperature  in  any 
considerable  space  for  a prolonged  time  is  attended 
with  some  difficulties.  The  first  attempts  were  made 
with  a small  gasoline  fired  assay  crucible  furnace  lined 
with  fire  clay  tiling  and  bound  with  sheet  iron.  With 
a 2 inch  Carey  burner  and  gasoline  at  20  lbs.  pressure 
a temperature  of  1400°  C was  obtained  in  the  focus  of 
the  burner  flame,  i.  e.  only  within  a small  space.  Only 
a few  briquettes  could  be  clinkered  in  this  way  while 
the  others  in  the  furnace  would  be  much  underburned. 
Another  difficulty  encountered  was  that  where  the  ce- 
ment briquettes  were  in  contact  with  the  furnace  lin- 
ing they  absorbed  silica  and  alumina,  thus  destroying 
the  original  composition  of  the  mixture,  and  causing 
them  to  “dust”  or  slough  away  on  cooling.  The  at- 
tempt to  burn  the  briquettes  in  a pot  furnace  in  direct 
contact  with  coke  proved  unsatisfactory  for  experi- 
mental purposes  as  the  amount  of  ash  absorbed  by  the 


OT/*TJ 

N01J.O3S  NyicJ 


45 


briquettes  was  such  as  to  cause  indefinite  results.  As 
a last  sesort  the  following  furnace  was  constructed. 
A graphite  crucible  was  cut  lengthwise  below  the 
median  line  and  the  larger  half  used.  A flue  opening 
was  made  at  the  top  near  the  closed  end.  Thoroughly 
burnt  coal  ashes  were  spread  on  a cement  top  table 
and  were  confined  by  a rectangle  of  fire  brick.  A layer 
of  chromite  brick  (a  neutral  refractory  substance) 
was  placed  on  the  ashes  and  formed  the  bottom  of  the 
furnace.  On  this  was  placed  the  improvised  graphite 
muffle  as  shown  in  the  accompanying  drawings.  The 
outside  walls  of  the  furnace  were  laid  up  of  fire  brick 
in  a mortar  of  fire  clay  and  cement.  The  space  be- 
tween the  walls  of  the  furnace  and  the  muffle  was 
filled  with  ashes  as  shown  in  the  drawing. 

The  flue  was  connected  by  pipe  to  the  chimney.  The 
only  opening  into  the  furnace  was  through  the  “burner 
boss”  which  was  made  of  a section  of  graphite 
crucible.  Whenever  the  furnace  was  charged  or  dis- 
charged the  burner  boss  was  removed,  giving  an  ample 
cylindrical  opening  into  the  muffle,  flush  with  the 
chromite  bottom.  The  firing  ./as  done  with  a 2 in. 
Carey  burner,  with  gasoline  as  fuel. 

The  burner  was  so  arranged  as  to  swing  readily 
away  from  the  burner  opening  and  leave  free  access 
to  the  furnace.  A porcelain  pyrometer  tube  reaching  to 
nearly  the  center  of  the  furnace  was  built  into  the  one 
side  wall  and  afforded  the  means  of  obtaining  the 
thermo-couple  readings  of  “burning.”  Gasoline  was 
burnt  under  a pressure  of  50  to  60  lbs.  per  sq.  in. 
In  order  to  burn  the  quantity  of  gasoline  implied  by 
this  pressure  in  a 2 in.  burner,  the  draft  in  the  fur- 
nace had  to  be  considerable.  This  was  obtained  by 
the  flue  connections  mentioned  above.  A uniform 
temperature  throughout  the  muffle,  of  nearly  1500°  C 
could  be  readily  obtained,  and  batches  of  cement  of 
2000  grams,  completely  and  readily  clinkered  in  from 
ij/2  to  2^4  hours.  The  cement  briquettes  never  ad- 


46 

hered  to  the  bottom  of  the:  furnace,  and  came  out 
perfectly  clean. 

Preparation  of  the  Cement  for  Testing. — The  ce- 
ment clinker  was  crushed  and  ground  in  the  Braun 
grinder,  to  pass  a 150  mesh  screen  thoroughly  mixed 
and  was  ready  for  testing.  Some  samples  of  it  were 
stored  before  testing,  others,  tested  without  storing. 


L-ONGTTUDINAL-  SECT/OM 

Tig.  8. 


PART  IV. 

EXPERIMENTAL  TESTS  ON  BLACK  HILLS 
CEMENT. 


MARK  EH  EE,  JR.,  E.  M. 


Testing. 

MARK  EHRE,  JR.,  E.  M. 

In  testing  the  Portland  Cement  manufactured  at 
the  State  School  of  Mines  the  object  was  to  determine 
its  suitability  as  a constructive  material,  within  limita- 
tions esablished  by  the  American  Institute  of  Civil  En- 
gineers, through  a committee  appointed  by  that  body  in 
1903.  To  1 his  end  all  methods  of  procedure  were  in 
accordance  with  the  specifications  by  them  adopted. 

The  properties  examined  and  reported  herein  in- 
clude the  following::  (1)  Color;  (2)  Specific  Grav- 
ity; (3)  Activity;  (4)  Soundness;  (5)  Strength. 

Color: — The  color  of  a cement  powder  indicates 
little  or  nothing  relative  to  its  cementitious  value  and 
is  of  importance  only  when  the  cement  is  to  be 
used  in  connection  with  exposed  portions  of  a struc- 
ture, a uniform  shade  being  desired.  All  the  cement 
made  at  the  School  of  Mines  was  of  the  greenish  gray 
shade,  characteristic  of  many  commercial  Portlands. 

Specific  Gravity — According  to  the  reports  of  the 
committee  above  mentioned,  the  determination  of  the 
Specific  Gravity  of  a cement  powder  gives  the  best  and 
quickest  test  for  underburning  or  adulteration;  the 
Specific  Gravity  of  an  underburned  or  impure  pro- 
duct being  usually  lower  than  for  the  normal  article. 
In  the  case  of  the  samples  herein  reported  the  main 
interest  lies  in  a comparison  with  well  established 
figures,  which  for  standard  brands  vary  from  3.10  to 
.3.25.  The  tests  for  Specific  Gravity  were  made  with 


50 

the  aid  of  the  simple  apparatus  designed  by  LeChate- 
lier,  and  shown  in  the  accompanying  Fig.  I.  It  con- 
sists of  a flask  (D)  having  a capacity  of  120  cubic  cen- 
timeters (72.32  cu.  in.),  the  neck  of  which  has  a diam- 
eter of  about  9 millimeters  (0.35  in)  and  is  expanded 
into  a bulb  (C)  about  midway  of  its  length.  The  vol- 
ume of  this  bulb  between  two  marks  at  (E)  and  (F) 
is  just  20  cubic  centimeters,  (1.22  cu.  in.)  and  gradu- 
ations on  the  tube,  reading  to  tenths  of  a cubic  centi- 
meter, are  continued  upward  from  (F).  The  small 
funnel  (B)  has  a tube  long  enough  to  extend  just  be- 
low (F). 

In  determining  the  Specific  Gravity  of  a cement 
powder,  the  flask  is  filled  with  kerosene  (free  from 
water,  to  the  point  (E).  The  sample,  having  been 
first  thoroughly  dried  and  brought  to  the  temperature 
of  the  liquid  in  the  flask,  a portion  equal  to  about  64 
grams  (2.25  oz.)  is  carefully  weighed  out  and  in- 
troduced into  the  flask  through  the  funnel  1(B).  The 
level  of  the  liquid  is  thus  raised  to  some  division  on  the 
graduated  neck  and  this  reading  added  to  20  gives 
the  total  volume  displaced  by  the  powder. 

The  Specific  Gravity  is  then  obtained  from  the 
following  formula : 

_ . Weight  of  Cement 

Specie  °raVlty=  Displaced  Volu^ 

During  the  test,  the  flask  is  kept  immersed  in  wa- 
ter in  the  jar  (A),  in  order  to  avoid  variations  in  the 
temperature  of  the  liquid  it  contains. 

Activity. — By  this  term  is  meant  the  rate  of  hard- 
ening of  a cement  after  being  made,  with  water,  into 
a paste  and  allowed  to  stand  undisturbed.  As  the  de- 
gree of  plasticity  of  the  paste  very  much  effects  the 
rate  of  hardening,  it  becomes  necessary  to  mix  all  sam- 
ples to  a uniform  or,  as  it  is  termed,  normal  consis- 
tency, in  order  to  establish  a basis  from  which  to  make 
observations.  The  test  for  activity  therefore  in- 


e 


FIG.  1 


cr  i r*  o 


5i 

eludes,  for  each  sample,  a preliminary  test  for  normal 
consistency. 

The  methods  employed  in  these  determinations  in- 
volved the  use  of  the  “Vicat  Needle”  apparatus 
its  suitability  as  to  constructive  material,  within  limita* 
shown  in  Fig.  2,  and  described  as  follows:  (L)  is  a 
movable  rod  which  may  be  adjusted  vertically  and  held 
in  any  position  by  the  set  screw  (F).  An  indicator 
attached  to  this  rod  moves  over  the  scale  (S)  which  is 
graduated  to  millimeters  and  attached  to  the  frame 
(K).  Into  the  lower  end  of  the  rod  may  be  inserted 
either  the  cylinder  (B),  1 centimeter  in  diam- 
ter  or  the  needle  (H)  one  millimeter  in 
diameter,  the  set  screw  (M)  securing  either 
piece  in  place.  Two  interchangeable  caps,  (C)  and 
(D)  of  different  weights  are  provided  and  suit- 
ably marked,  one  for  use  in  connection  with  the 
cylinder  and  the  other  with  the  needle ; the  combina- 
tion of  cap,  rod  and  needle,  assembled  as  shown, 
weighing  just  300  gramms  (10.58  oz.)  which  is  also 
the  weight  of  the  combined  cap,  rod  and  cylinder.  A 
conical  rubber  ring  (1),  7 centimeters  (2.76  in.)  in 
diameter  at  the  base  and  4 centimeters  (1.58  in.)  high 
rests  on  the  glass  plate  (J)  and  retains  the  paste  which 
is  to  be  tested. 

In  making  the  determination  for  normal  consis- 
tency, about  500  gramms  (17.58  oz.)  of  the  cement 
p(  v der  are  quickly  worked  into  a thick  paste,  formed 
into  a ball  with  the  hands  and  pressed  into  the  rub- 
ber ring  through  the  larger  opening,  smoothed  off  and 
the  face  covered  with  the  glass  plate;  plate  and  ring 
are  then  turned  over  and  the  smaller  opening  smooth- 
ed off  with  a spatula  or  trowel.  The  paste  confined 
in  the  ring  is  then  placed  under  the  rod,  bearing  the 
cylinder  and  corresponding  cap,  the  bottom  of  the 
cylinder  being  brought  just  into  contact  with  the  sur- 
face of  the  paste  and  quickly  released.  By  definition 
the  paste  has  a normal  consistency  when  the  cylinder 


1. 


52 

penetrates  the  mass  to  a depth  of  io  millimeters 
(0.39  in). 

These  trial  pastes  are  made  up  with  varying  per- 
centages of  water  until  the  proper  consistency  is  ob- 
tained. In  making  the  test  for  activity  the  cylinder 
(B)  is  replaced  by  the  needle  (H),  and  the  cap  (D) 
replaces  (A).  The  ring  is  then  tilled  with  paste  of 
normal  consistency,  carefully  smoothed  off,  and  placed 
under  the  rod.  At  lengthening  intervals  of  time  the 
needle  is  brought  just  into  contact  with  some  point  of 
the  surface  and  quickly  released.  The  setting  is  said 
to  have  commenced  when  the  needle  ceases  to  pass  a 
point  5 millimeters  (0.20  in.)  above  the  upper  surface 
of  the  glass  and  is  said  to  have  terminated  the  mo- 
ment the  needle  does  not  visibly  sink  into  the  mass. 
The  two  points  thus  observed  are  termed  the  initial 
and  final  set,  respectively,  and  the  time  of  each  period 
is  to  be  noted  from  the  instant  of  first  addtion  of  water 
to  the  mixture.  The  time  of  initial  set  varies  widely 
in  different  cements,  ranging  from  15  minutes  to  12 
hours  and  if  of  great  importance  in  that  it  marks  the 
time  after  which  no  internal  disturbance  of  the  mass 
should  occur. 

The  final  set  marks  the  point  when  real  harden- 
ing has  commenced  which  hardening  process  rhay  not 
be  complete  for  years.  The  test  pieces  should  in  all 
cases  be  kept  damp  or  immersed  in  water  during  the 
period  of  testing. 

Soundness. — By  this  term  is  meant  the  ability  of 
the  cement  to  retain  its  strength  and  form  indefinite- 
ly. Any  tendency  to  swell,  crack  or  disintegrate,  after 
the  mass  has  set,  indicates  failure  in  his  respect. 

As  unsoundness  is  frequently  caused  by  the  pres- 
ence in  the  cement  of  some  active  agent  such  as  free 
lime  or  magnesia  and  as  the  evil  effects  of  these  ele- 
ments would,  under  normal  conditions,  not  be  mani- 
fest for  a considerable  period,  it  becomes  desirable  to 
accelerate  their  action  and  by  thus  noting  the  behavior 
of  the  cement  over  a relatively  short  period,  under 


FIG  3 


FIG  4 


53 

abnormal  conditions,  determine  what  would  probably 
be  their  action  over  a long  period  under  normal  con- 
ditions. 

This  accelerating  action  is  usually  effected  by  the 
use  of  heat,  the  test  being  made  as  follows.  From  a 
paste  of  normal  consistency  a number  of  lens  shaped 
patties  are  moulded  on  watch  glasses,  each  sample  be- 
ing smoothed  out  to  a thin  edge  around  its  circum- 
ference. These  patties  are  then  set  aside  in  a moist 
atmosphere  until  quite  hard.  These  samples,  still  ad- 
hering to  the  glasses,  are  then  placed  in  a vessel  of 
water,  the  temperature  of  which  is  gradually  raised  to 
the  boiling  point  and  maintained  there  for  at  least 
three  hours.  To  pass  a satisfactory  test  the  patties 
should  remain  intact  without  any  sign  of  cracking, 
disintegration  or  distortion. 

Strength. — The  tests  for  strength  were  made  by 
submitting  moulded  specimens,  having  a minimum 
cross  sectional  area  of  one  square  inch,  to  a tensile 
stress  sufficient  to  rupture  them,  and  noting  the  magni- 
tude of  such  stress,  for  file  purpose  of  comparison.  On 
account  of  the  lack  of  suitable  apparatus,  no  tests  of 
crushing  strength  were  made.  Extensive  investiga- 
tion has  shown,  however,  that  the  resistance  in  com- 
pression may  be  assumed  as  about  ten  times  that  in 
tension. 

In  the  case  of  each  batch  of  cement  burned,  tests 
were  made  on  specimens  made  from  the  pure  or 
“neat”  cement  and  also  on  specimens  of  mortar,  com- 
posed of  certain  percentages  of  cement  and  standard 
sand.  By  standard  sand  is  meant  a clean,  sharp  sand, 
all  of  which  will  pass  a twenty  mesh  and  remain  on 
a thirty  mesh  screen.  The  effect  of  age  was  also  con' 
sidered,  specimens  being  tested  at  seven  and  also  at 
twentyeight  days  from  time  of  mixing. 

The  form  of  mould  used  in  making  the  briquettes 
or  test  pieces  is  shown  at  (A),  Fig.  3,  the  samples  being 
retained  in  the  moulds,  in  a damp  atmosphere,  until 
hard,  when  they  were  removed  and  kept  under  water 


54  . 

until  tested.  Fig.  4 shows  the  feature  of  one  of 
these  standard  briquettes. 

The  machine  used  in  making  these  tests,  the  prop- 
erty of  the  School  of  Mines,  is  the  standard  type  man- 
ufactured by  Riehle  Bros,  of  Philadelphia^  Pa.,  and  has 
a capacity  of  2000  lbs.  It  is  shown  in  Fig.  5.  In  oper- 
ating, the  briquette  to  be  tested  is  introduced  into  the 
clips  or  jaws  at  (A)  (also  shown  in  detail  in  Fig.  6). 
By  means  of  a small  hand  wheel  operating  the  worm 
gear  at  (C),  a gradually  increasing  tensile  stress  is 
brought  to  bear  on  the  specimen,  this  stress  being  coun- 
terbalanced, through  a compound  lever,  by  the  rider 
(R)  running  on  the  graduated  beam  (D),  the  position 
of  the  rider  being  controlled  by  the  small  hand  wheel 
(W).  and  exact  equilibrium  being  at  all  times  main- 
tained by  observing  the  pointer  (P).  The  stress  is 
increased  slowly  and  uniformly  until  rupture  of  the 
piece  occurs,  the  stress  producing  it  being  then  read 
directly,  in  pounds,  from  the  position  of  the  rider  on 
the  beam. 

Results. — In  all,  some  thirteen  batches  of  cement 
were  burned  and  tested,  the  results  obtained  from  five 
of  them  being  shown  in  the  following  tabular  view. 


FIG.  5 


V 


f 

/ 


i 

I 


ss 


UNIVERSITY  OH  ILLINOIS 


PRESIDENTS  office. 


